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authorAndi Kleen <ak@suse.de>2006-06-26 13:56:10 +0200
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-26 10:48:14 -0700
commitfaee9a5dc9d8399cc3b1b8e18b6d7ff7b17f1af1 (patch)
treee909f4ca48bd3d61b06e3b77f4c380301cd7b857 /arch/x86_64/kernel
parent79121ea9f098934850347eeed3857ffd836810c3 (diff)
[PATCH] i386/x86-64: Use new official CPUID to get APICID/core split on AMD platforms
Previously the apicid<->coreid split was computed based on the max number of cores. Now use a new CPUID AMD defined for that. On most systems right now it should be 0 and the old method will be used. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/x86_64/kernel')
-rw-r--r--arch/x86_64/kernel/setup.c20
1 files changed, 13 insertions, 7 deletions
diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index fb850b52b4d..1cb3e21c571 100644
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -873,10 +873,18 @@ static void __init amd_detect_cmp(struct cpuinfo_x86 *c)
int node = 0;
unsigned apicid = hard_smp_processor_id();
#endif
+ unsigned ecx = cpuid_ecx(0x80000008);
- bits = 0;
- while ((1 << bits) < c->x86_max_cores)
- bits++;
+ c->x86_max_cores = (ecx & 0xff) + 1;
+
+ /* CPU telling us the core id bits shift? */
+ bits = (ecx >> 12) & 0xF;
+
+ /* Otherwise recompute */
+ if (bits == 0) {
+ while ((1 << bits) < c->x86_max_cores)
+ bits++;
+ }
/* Low order bits define the core id (index of core in socket) */
cpu_core_id[cpu] = phys_proc_id[cpu] & ((1 << bits)-1);
@@ -964,11 +972,9 @@ static int __init init_amd(struct cpuinfo_x86 *c)
if (c->x86_power & (1<<8))
set_bit(X86_FEATURE_CONSTANT_TSC, &c->x86_capability);
- if (c->extended_cpuid_level >= 0x80000008) {
- c->x86_max_cores = (cpuid_ecx(0x80000008) & 0xff) + 1;
-
+ /* Multi core CPU? */
+ if (c->extended_cpuid_level >= 0x80000008)
amd_detect_cmp(c);
- }
return r;
}